The field of the present invention is monitoring devices for sensing pressure in engine lubricating systems. Oil pressure sensing systems have long been employed in automobile engines and the like for sensing the pressure of the lubricant within the system. Such devices include warning systems which include a warning lamp which is activated by a reduction in pressure below a predetermined value. Thus, when oil pressure reaches a dangerously low level which would result in damage to the engine under continued operation, a warning light indicates the condition to the operator. Once such device is illustrated in FIGS. 1 and 2.
In FIG. 1, a cross section of an engine is illustrated with a lubricant supply system 10 directing oil through an oil hole 12 to a bearing 14. The oil continues through a sensor passage 16 to an oil switch 18. Extending outwardly from the engine case, the switch 18 is in communication with the sensor passage 16. A switch is schematically illustrated in FIG. 2. The switch may employ a spring which stretches back and forth and responds to changes of oil pressure above and below a preset level. A metal terminal communicates with the warning lamp circuit to provide a signal responsive to the movement of the spring.
The switch as illustrated in FIGS. 1 and 2 is commonly employed on automobiles and motorcycles. Because of the necessity to check and repair such switches, these switches are normally positioned such that they may be easily reached by a mechanic for checking and replacement. This location is often inconvenient, requires additional lubricant passages, is more expensive and may require placement in a disadvantageous position. The device of FIG. 1 provides an example of these difficulties where the engine case must be cored or drilled and tapped to provide for the convenient location of the switch which is awkwardly extending from the engine.